Pedro Hernandez’s estranged daughter was shattered to hear that her father confessed to the murder of Etan Patz, her mother-in-law told The Post.

“She’s a mess. She can hardly speak. She didn’t know her father was a killer. She hardly knew him at all,” said the mother-in-law, who would not give her name. Nathalie Hernandez, 27, of Pennsauken, NJ, hasn’t had any contact with her father in years. She is a “wonderful wife and mother,” the woman said yesterday.